import numpy as np
import pandas as pd
s = pd.Series([0,1,1,3,3,3,np.nan,np.nan])
print(s.size)  #数据数量
print(s.count())
print(s.unique())
print(s.value_counts())
print(s.value_counts())
print(s.head(2))
print(s.take([0,2]))
